I agree with your strategy (drag feet and affirm or decline only when necessary). I agree Hillary is more likely than any of the Republicans to win the Presidency. I will disagree, however, that she is more centrist than Obama. Obama gave us Sotomayor, and the only reason he's pushing Garland is to try and get some political points (he knows the Reps won't want to confirm any of his nominees). I think Clinton would likely nominate a more liberal hawk than Garland, however. She has more "stones" than Obama, and it would be something of a vengeance nomination, I'd guess.
McConnell & Co. broadcasting their strategy was strongly inadvisable. They should have just said "We'll consider any nominee and vote appropriately". Then, vote them down as necessary. Unless, of course, their whole plan was to get a more moderate nominee... in which case, they better take Garland while they can
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As to Garland, himself: he seems more reasonable than I would have hoped to expect from an Obama nominee. He seems less "judicial activist" and more "pragmatist" than Kagan, and certainly more than Sotomayor. I've gone back and forth on him already. I'd say, string this along as long as possible - if Trump's odds suddenly improve, maybe vote him down. If, the odds continue to look like Clinton will win, I'd say vote and confirm the guy.
We'd never get another Scalia confirmed, anyway (assuming President Trump would nominate such a justice). What we saw as "Constitutional originalism" has been described as "racist bigotry" in many circles.